Background

A large number of stand alone power systems (SAPS) are installed around Europe. These systems provide power to technical installations and communities in remote areas. The power range varies from less than a kW and up to several hundred kW. An increasing number of SAPSs include renewable energy technologies, i.e. solar or wind power, most often in combination with diesel generators and/or batteries for backup power. However, the majority of larger SAPS are still based on fossil fuel power generation.

Hydrogen can be produced from renewable energy (RE) at the site and used for power production in fuel cells in periods with limited RE availability. Using hydrogen as energy storage could increase the RE utilisation up to 100%. Replacing diesel generators and batteries in SAPS would diminish fossil fuel dependence, improve environmental standards, and possibly reduce operation and maintenance costs. The fuel cell technology is developing fast and the SAPS market is believed to be a market segment where this new technology can be competitive in the near future. However, there seems to be significant barriers in the SAPS market that can slow down and limit the introduction of hydrogen energy technology, thus also the RE energy utilisation in remote power production.

It is not only the RE availability that governs the technology penetration in the market. The choice of SAPS technology differs significantly depending on the location and power demand characteristics. In Northern Europe for example, most SAPSs are based on PV arrays with a large battery bank. In Norway more than 2000 beacons and light houses along the coast are powered by solar energy and about 100 000 leisure homes and mountain cabins have a small PV power unit. Diesel generators or wind/diesel hybrids are less common. In Greece on the other hand, diesel generators cover the largest part of the stand-alone market. There are only a few wind-diesel hybrids (total power of 200kW) and a few PV + batteries installations (another 300 kW).

The cost of installing a SAPS is significant. Additionally, the maintenance can be labour intensive. Spare parts and repairs for diesel engines and frequent battery replacements are typical additional costs for the systems. These factors add to the energy price the customer has to pay, but also reduces the availability (running time) and reliability of the installation. Replacing the diesel generator and the battery bank in SAPSs with technology which is cheaper and more reliable would be an important step forward.

Hydrogen is the ideal clean fuel for the future. Hydrogen can be produced from RE by water electrolysis at almost any location. Hydrogen can be stored in pressurised vessels, as a liquid, in metal hydrides or as chemical compounds. In periods with less RE power available the chemical energy of hydrogen can be converted to power in a fuel cell. In the stand alone power market, hydrogen is seen as a key to increased RE utilisation. It is also important for the long term development of the RE market. An intermediate storage of energy is required to account for the fluctuations in solar and wind power production in addition to variations in the user power demand. Introducing hydrogen subsystems in SAPS installations could thus pave the way for 100 % RE power supply in this market. Hydrogen is also seen as the most environmentally friendly fuel for vehicle propulsion. The international car industry is investing strongly in the development of hydrogen and fuel cell technology.

Water electrolysis and hydrogen storage are well established technologies which have been on the commercial market for many decades. These technologies have proven reliable and affordable for a wide range of applications. However, fuel cell technology is only available on a pre-commercial scale. A few manufacturers can provide limited numbers of fully operating fuel cell power units. Nevertheless, the technology is developing fast. Many fuel cell manufacturers both in Europe and overseas have announced market introduction of commercial units within 1 to 5 years. As fuel cells are becoming available, all the components necessary to integrate hydrogen energy subsystems in SAPSs are at hand. Due to the technological and economical characteristics of remote power supply, it is reasonable to assume that the SAPS market can play an important role in the market development for fuel cell and hydrogen technology in the years ahead. This would be a situation similar to what has been observed with respect to the photovoltaic solar power market over the last decades. The introduction of PV power units in various high cost niche applications have significantly encouraged the technology development thus bringing the price down opening new markets.

Preliminary estimates of the European RE hydrogen SAPS market suggest a market value in the order of 50 billion Euro. Although this is a rough estimate, the economical and technological impact of introducing hydrogen technology is obvious.

However, there seems to be significant barriers in the SAPS market that slow down and limit the introduction of hydrogen energy technology, thus also the RE energy utilisation in remote power production. The barriers are believed to be related to uncertainty about the market value, lack of technological standards, economy and to some extent, public policies.

A study of the potential for replacing diesel engines and battery banks with hydrogen sub-systems would therefore be of great interest to industry and authorities. Such a study would benefit the development of the RE and fuel cells markets.

Very few studies are known to exist which have any degree of relevance, and they are based on rather rough estimates about the technological solutions and demographic data, for example not taking into account projections for population and energy consumption development in remote communities. To our best knowledge no investigations have covered the whole European renewable energy H-SAPS market including both solar and wind power. The previous studies do not present analyses of the market barriers and are insufficient as tools for market strategy development for the key commercial actor and policy development for the authorities.

There have been initiatives to work on hydrogen technology standardisation on a European level as well as national levels. However, much of this work has dealt with automotive applications. It is still a major challenge in stationary power demonstration projects to fit the various components efficiently together.